<!DOCTYPE html>
<html lang="en">
<head>
    <meta charset="UTF-8">
    <title>Document</title>
</head>
<body>
    <div id="app">
        <form action="">
            <input type="text" v-model="number" />
        </form>
        <div v-bind="number"></div>
        <div v-bind="number"></div>
    </div>
    <script>
        function myVue(options) {
            this._init(options);
          }

  myVue.prototype._init = function (options) {
    this.$options = options;
    this.$el = document.querySelector(options.el);
    this.$data = options.data;
    this.$methods = options.methods;

    this._binding = {};
    this._obverse(this.$data);
    this._complie(this.$el);
  }
 
  myVue.prototype._obverse = function (obj) {
    var _this = this;
    Object.keys(obj).forEach(function (key) {
      if (obj.hasOwnProperty(key)) {
        _this._binding[key] = {                                   
          _directives: []
        };
        console.log(_this._binding[key])
        var value = obj[key];
        if (typeof value === 'object') {
          _this._obverse(value);
        }
        var binding = _this._binding[key];
        Object.defineProperty(_this.$data, key, {
          enumerable: true,
          configurable: true,
          get: function () {
            console.log(`${key}获取${value}`);
            return value;
          },
          set: function (newVal) {
            console.log(`${key}更新${newVal}`);
            if (value !== newVal) {
              value = newVal;
              // 更新DOM结构的
              binding._directives.forEach(function (item) {
                item.update();
              })
            }
          }
        })
      }
    })
  }

  myVue.prototype._complie = function (root) {
    var _this = this;
    var nodes = root.children;
    for (var i = 0; i < nodes.length; i++) {
      var node = nodes[i];
      if (node.children.length) {
        this._complie(node);
      }

      if (node.hasAttribute('v-click')) {
        node.onclick = (function () {
          var attrVal = nodes[i].getAttribute('v-click');
          return _this.$methods[attrVal].bind(_this.$data);
        })();
      }

      if (node.hasAttribute('v-model') && (node.tagName == 'INPUT' || node.tagName == 'TEXTAREA')) {
        node.addEventListener('input', (function(key) {
          var attrVal = node.getAttribute('v-model');
          _this._binding[attrVal]._directives.push(new Watcher(
            'input',
            node,
            _this,
            attrVal,
            'value'
          ))

          return function() {
            _this.$data[attrVal] = nodes[key].value;
          }
        })(i));
      } 

      if (node.hasAttribute('v-bind')) {
        var attrVal = node.getAttribute('v-bind');
        _this._binding[attrVal]._directives.push(new Watcher(
          'text',
          node,
          _this,
          attrVal,
          'innerHTML'
        ))
      }
    }
  }

  function Watcher(name, el, vm, exp, attr) {
    this.name = name;         //指令名称，例如文本节点，该值设为"text"
    this.el = el;             //指令对应的DOM元素
    this.vm = vm;             //指令所属myVue实例
    this.exp = exp;           //指令对应的值，本例如"number"
    this.attr = attr;         //绑定的属性值，本例为"innerHTML"

    this.update();
  }

  Watcher.prototype.update = function () {
    console.log('test')
    this.el[this.attr] = this.vm.$data[this.exp];
  }

  window.onload = function() {
    var app = new myVue({
      el:'#app',
      data: {
        number: 0,
        count: 0,
      },
      methods: {
        increment: function() {
          this.number ++;
        },
        incre: function() {
          this.count ++;
        }
      }
    })
  }
    </script>
</body>
</html>